This invention relates to a drive train for an articulated vehicle of the type having a first vehicle section with a rotatable driving unit (e.g., a transmission) and a second vehicle section with a rotatable driven unit (e.g., a differential). The second vehicle section is connected to pivot relative to the first section about an upright axis which is located generally between the driving and driven units when the two vehicle sections are in line with one another.
The driving and driven units are connected by a drive train which transmits power from the driving unit to the driven unit while allowing the second vehicle section to pivot or articulate relative to the first vehicle section. A typical drive train includes a first shaft having one end connected to the transmission or other driving unit of the first vehicle section by a universal joint. A second shaft is supported by a fixed bearing on the second vehicle section and usually is connected to the differential or other driven unit of the second vehicle section by another universal joint. Yet another universal joint serves to connect adjacent ends of the two shafts.
Conventional drive trains of the type described above are relatively complex and expensive. In a conventional drive train, each of the two shafts is formed at least in part by two telescoped splined components (e.g., a splined male or shaft component and a splined female or sleeve component). The splines transmit rotation between the shaft and sleeve components and allow such components to slide axially relative to one another. While the splined components of the second shaft remain axially fixed after installation and during articulation of the second vehicle section, the splined components of the first shaft slide axially relative to one another to accommodate the articulation. Such relative sliding enables the first shaft to change in effective length such that, at any articulation angle, the universal joint angle at one end of the shaft is equal and opposite to that at the other end of the shaft. This insures that there are no speed fluctuations in the transmitted power regardless of the degree of articulation of the second vehicle section.